grave spire
You are a useless neutral until someone tries to kill you.
If someone tries to kill you for the first time you will be tpd out of the map and when the meeting is called you will be tpd back in (if this is not possible then just block any attack until the meeting is called). During meeting a random role will be assigned to you (that has not spawned in the game). Now you win according to your new role.
Basis : make it whatever, the random role that is assigned will be chosen accordingly.
Win condition : Change roles and win according to the new role. If you were unable to change role, you will not win
Edit : in case number of unique roles that are on is less than the total number of players, then just choose one role that has already spawned.